package cn.tedu.sp06.fb;

import cn.tedu.web.util.JsonResult;
import lombok.extern.slf4j.Slf4j;
import org.springframework.cloud.netflix.zuul.filters.route.FallbackProvider;
import org.springframework.http.HttpHeaders;
import org.springframework.http.HttpStatus;
import org.springframework.http.client.ClientHttpResponse;
import org.springframework.stereotype.Component;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

@Component
@Slf4j
public class ItemFB implements FallbackProvider {
    /**
     * 设置针对哪个后台服务进行降级
     *
     *   item-service: 只针对商品服务进行降级
     *   "*": 对所有服务都应用当前降级类
     *   null: 对所有服务都用用当前降级类
     * */
    @Override
    public String getRoute() {
        return "item-service";
    }

    /**
     * 向客户端发回的降级响应
     *   - 错误提示
     *   - 缓存数据(访问redis获取缓存中的数据)
     *   - 根据业务逻辑返回任意数据
     * */
    @Override
    public ClientHttpResponse fallbackResponse(String route, Throwable cause) {
        return new ClientHttpResponse() {
            @Override
            public HttpStatus getStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR;
            }

            @Override
            public int getRawStatusCode() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.value();
            }

            @Override
            public String getStatusText() throws IOException {
                return HttpStatus.INTERNAL_SERVER_ERROR.getReasonPhrase();
            }

            @Override
            public void close() {

            }

            @Override
            public InputStream getBody() throws IOException {
                //JsonResult - {code:500, msg:xxx, data:null}
                String json = JsonResult.err().code(500).msg("后台服务器出错,请稍后重试").toString();
                return new ByteArrayInputStream(json.getBytes("UTF-8"));
            }

            @Override
            public HttpHeaders getHeaders() {
                //Content-Type: application/json;charset=UTF-8
                HttpHeaders h = new HttpHeaders();
                h.add("Content-Type", "application/json;charset=UTF-8");
                return h;
            }
        };
    }
}
